Term
| Components of the Urinary System |
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Definition
1. Kidney
2. Ureter
3. Bladder
4. Urethra |
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Term
| Origin of urogenital structures |
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Definition
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Term
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Definition
From superior to inferior
1. Pronephros
2. Mesonephros
3. Metanephros |
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Term
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Definition
Develops about the 4th week
Located in the cervical region
Rudimentary and nonfunctional
Regress by the end of the 4th week |
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Term
| Mesonephros and Mesonephric Duct (Wolffian Duct) |
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Definition
Acts as a temporary kidney before being replaced by metanephric structures.
Develops tufts of capillaries at medial end to bring blood to early kidney corpuscle (early form of nephron). Caudal tubules form as cranial ones disappear.
Lateral end forms mesonephric duct.
Mainly disappears except for in males: part of duct and collecting tubules for the ejaculatory duct of the male. |
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Term
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Definition
Forms the definitive kidney. Starts in pelvic region.
Duct system and excretory system forms differently. |
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Term
| Development of excretory portion of kidney |
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Definition
Induced by developing tubules.
Metanephric tissue caps form around collecting tubules, form into nephrons.
Must find a way to connect to the collecting duct. |
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Term
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Definition
| Distinct from the excretory portion of the kidneys, goes on to form the ureter, calyces, and the pelvis. |
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Term
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Definition
| Occur when the excretory portion of the kidney fails to connect to the ductal portion. Urine has no way of leaving the kidney and forms cysts. Growth of the cyst is limited by pressure, when pressure builds up in the nephron, capillaries can no longer contribute more fluid and filtering stops. This limits the size of the cysts. |
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Term
| Molecular regulation of mesenchymal to epithalial transformation of collecting duct |
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Definition
Mesenchymal to epithelial transformation of the collecting duct.
Mesenchyme (nephron) secretes WT1-> induces GDNF and HGF production.
These go to GDNF and HGF receptors of uroteric bud (which develops into the collecting duct), which makes them secrete FGF and BMP and induces mesenchymal transformation. |
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Term
| Multicystic dysplastic kidney |
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Definition
| Numerous ducts surrounded by undifferentiated mesenchyme. No nephrons. May lead to involution and renal agenesis. |
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Term
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Definition
1. Failure of development of the kidneys leads to poor urine production.
2. Urine forms a major component of the amniotic fluid.
3. Less amniotic fluid is produced (oligohydramnios), which reduces flow to the lungs.
4. Leads to pulmonary hypoplasia.
5. Also leads to GU anomalies. |
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Term
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Definition
Wilm's Tumor
Occurs due to mutations in WT1 or WT2 genes.
Associated with other abnormalities (WAGR and Denys-Drash Syndrom)
Presents as an asymptomatic mass, hard to detect. |
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Term
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Definition
| Wilms, Aniridia (absence of iris), GU anomalies, mental retardation |
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Term
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Definition
| Pseudohermaphrodism, renal failure, Wilms |
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Term
| Development of the collecting system |
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Definition
Develops from the ureteric bud (branches from the mesonephric duct).
Penetrates metanephric tissue and undergoes 12 generations of budding.
2nd order tubules enlarge to absorb the 3rd and 4th generations and form minor calyces
5th+ generations elongate and drain into the minor calyces forming the renal pyramid, form the pelvis of the kidney. Later generation branches drain into earlier generation branches. |
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Term
| Kidney Ascent and Rotation |
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Definition
Kidney starts in pelvis, needs to ascend. As it ascends, it gets new blood supply from the aorta. Also rotates inwards, pelvis rotates toward the medial aspect of the body. Kidney initially have lobulations that disappear in adult.
Kidney on left slightly higher than right normally due to liver, restricts right ascension slightly. Ascent of kidneys limited by other abdominal structures. |
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Term
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Definition
Last portion of the endoderm, intersection of the urethra and the bladder before urorectal septation.
Urorectal septum divides the cloaca into the anal canal and the UG sinus.Ureteric bud drains into the anterior portion of the cloaca. |
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Term
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Definition
| Location where the urorectal septum meets the skin. |
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Term
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Definition
| Defect in urorectal septation, septum doesn't make it all the way to the skin (Rectoperineal) |
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Term
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Definition
| Bladder may have septation within it. |
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Term
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Definition
| Persistent cloaca with failure of mesodermal closure over the endoderm. Gaping hole occurs in the abdomen/pelvis. |
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Term
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Definition
| Upper part of the UG sinus created by urorectal septation becomes the bladder. Connected to the urethra and the allantois (connects through the umbilical cord to become the urachus). |
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Term
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Definition
Urachal sinus, doesn’t communicate with bladder.
Urachal cyst closed at both ends, but cells inside urachus make fluid, creates cyst.
Persistant urachal opening to cut umbilical cord, can leak from bellybutton, smells like ammonia. |
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Term
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Definition
| Lower part of the UG sinus. |
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Term
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Definition
Mesonephric duct goes to posterior bladder.
Ureteric bud branches off and attaches to posterior bladder and forms ureter.
These form trigone of the bladder.
Trigone lining initially mesodermal in origin and then become replaced by endodermal lining. |
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Term
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Definition
| Can have two ureters that form. Upper pole ureter drains lower, usually inserts abnormally to bladder (ectopically), drains abnormally, creates distension. Can insert below sphincter so constant dibble of urine. Also overdevelopment can cause urine reflux back into kidneys. |
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